Characterization of a Β-glucosidase from Paenibacillus species and its application for succinic acid production from sugarcane bagasse hydrolysate

In this study, a β-glucosidase from Paenibacillus sp. M1 was expressed in E. coli BL21(DE3), purified and characterized. The specific activity of purified BglA was 137.64 U·mg⁻¹ protein with optimal temperature and pH of 50 °C and 6.0. Furthermore, BglA shows excellent adaption to various environmental factors such as temperature, pH and metal ions. Engineered E. coli Suc260 was further reconstructed by overexpressing the β-glucosidase for achieving direct cellobiose utilization, which could efficiently utilize the pretreated sugarcane bagasses hydrolysate (SBH) consisting of 25.30 g·L⁻¹ cellobiose, 9.70 g·L⁻¹ glucose, 5.90 g·L⁻¹ arabinose and 7.10 g·L⁻¹ xylose. As a result, 26.50 g·L⁻¹ and 24.30 g·L⁻¹ succinic acid were produced by strain Suc260(pTbglA) from cellobiose and SBH with corresponding yields of 88.30% and 89.20% using dual-phase fermentation, respectively. This study indicated that incomplete enzymatic hydrolysate of SCB will be a potential feedstock for succinic acid production.